Resigned and employer is hostile

I resigned 3 weeks ago on a HENRY job of £220k to pursue a better opportunity. Initially things were fine but my employer(HR and a senior person who joined 6 months ago) started to become very hostile.

The HR is telling me not to take annual leaves and this senior person is picking on me while I am trying to do a proper handover. I do not wish for any conflict and I am worried he goes crazy with his aggro and makes my life difficult during my 3 month notice. Has anyone experienced this? What are the choices?